She was arrested in December 2014 on charges of embezzlement, illegal business activity, tax evasion and abuse of power, which international rights groups have denounced as trumped-up.

In September 2015, a court in Azerbaijan convicted Ismayilova, a contributor to US government-funded Radio Free Europe/Radio Liberty, of several financial crimes and sentenced her to seven-and-a-half years in prison.

On Wednesday, Azerbaijan's Supreme Court ruled to replace that with a three-and-a-half-year suspended sentence and ordered her release on probation. The court set a five-year period for her probation.

'Release all journalists'

Rights groups have criticised the Azerbaijani government for cracking down on independent media and opposition activists. Several other journalists and rights activists also have been imprisoned in what has been widely seen as an effort by the government to stifle dissent.

"Today's ruling ordering Khadija Ismayilova freed is cause for celebration, but doesn't erase the rank injustice of her imprisonment for a year and a half on retaliatory charges," said Nina Ognianova, a Europe and Central Asia programme coordinator of the Committee to Protect Journalists.

"We call on Azerbaijani authorities to remove the conditions on her freedom, and to release all journalists imprisoned for their work immediately."